Improvement in slide-valves for steam-engines



UNITED STATES PATENT OFFICE.

SAMUEL E. I-IoDeE, on DETROIT, MICHIGAN. i

IMPROVEMENT IN SLIDE-VALVIES FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 49,267, dated August 8, 1865.

. provement in Slide-Valves of Steam-Engines; and I do hereby declare th at the following is a full,`clear, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in i which-- jFigure 1 is a longitudinal section taken in a vertical plane through the improved valve.

' Fig. 2 is a top view of Fig. 1.

Similar letters of reference indicate corresponding parts in the two figures.

This invention relates to an improvement on slide-valves, which are relieved of undue steampressure by means of a hollow follower that is applied to the back of the valve and acted upon by means of an adjusting-screw, through the medium of a spring, which allows the valve to rise from its seat when necessary, and then forces it back to its seat.

The object of my invention is to diminish the pressure of steam upon the back of a slidevalve by means of a hollow lian ged follower, which is held down upon the back of the valve by means of an adjustable stuffing-box gland, which is made to act upon the flange of the follower through the medium of an interposed elastic substance, as will be hereinafter described.

To enable others skilled in the art to understand my invention, I will describe its construction and operation. .i

The steam-chest A is constructed with an opening through its top which is surrounded by a anged neck, B, through which a hollow flanged follower, C, passes, as shown in Fig.

1. The lower flanged end of the follower Gis forced down upon the back of the slide-valve D by means of a Banged gland, E, between which and the flange a of the follower C is interposed india-rubber or other elastic substance, as indicated atb, Fig. 1, for the purpose of actin g upon the follower with an elastic pressure. y

The flange of the gland E projects over the flange of the neck or stufng-box B, and receives through it screws c c, upon the ends of which nutsd d are screwed. By means of these screws and nuts the gland E can be forced down upon the flange a of the follower, and this latter caused to press upon the back of the slide-valve D ith any desired degree of force. At the same time the elastic substance b will be compressed and form a steam-tight packing around the circumference of the follower.

The area of the back of the valve D is somewhat greater than the area of the opening into the bottom of the follower G, so that this opening will not be exposed by the sliding movements of the valve.

The back of the valve may be enlarged in area by the application of a dat plate to it, as

shown in Fig. l, extending beyond both ends lower that the gland E will 'act directly upon it near its lower end is that this follower will be held down upon the back of the valve with a uniform pressure at all points, and consequently the follower will not be liable to tilt and wear uneven or bind upon any one portion of the valve more than on another.

The object of the hollow follower is to prevent steam-'pressure upon the back o'f the valve by excluding steam therefrom, and it is important to provide for holding the valve down upon its seat squarely, so that the surface ot' the valve will wear perfectly true. This can be done by the application ofthe adjustable gland to the circumference and near the lower end of said follower in a much better manner than by the use of a single center adjustingscrew acting upon the upper end of the follower, as hitherto.

The packing b, which is interposed between the flange of the follower and the lower end of the stuffing-box gland, is expanded in theact of forcing the follower down upon the back of the valve, and forms a steam-tight packing.

It also serves as a spring to allow the valve to follower O, packing 1),' stuffing-box B, adjustlift from its seat under extraordinary circumablegland E, and valve D, substantially as stances. described.

Having thus described my invention, what SAML. F. HODGE. I claim as new, and desire to secure by Letters Witnesses: Patent, is l THos. S. GHRIs'rrE,

The combination and arrangement of the PORTER L. WEED. 

